The increase in awareness of the health risks inherent in air pollution recently has caused many people to reassess the quality of their indoor air and environment. Recent Environmental Protection Agency studies indicate that indoor air pollution levels could be 2-5 times higher than the ambient outdoor air pollution level. It is estimated by some that, on rare occasions, these indoor air pollution levels can be 100 times higher than outdoor air pollution levels. This is an increasingly important matter that must be addressed, because many people, especially infants and the elderly, spend more than 90% of their time indoors. Some of these indoor pollutants could also be contributing factors to frequent and unexplained headaches or sleepless nights that afflict numerous persons within the general population.
There are numerous devices in the prior art that are designed and manufactured for purifying indoor air. With more homes and offices becoming better insulated, an objective of air purifiers is to clear the indoor air of common pollutants, including dust, smoke, pollen, bacteria, soot, mold spores, animal dander, and other microscopic irritants, and thereby create a clean, healthy, fresh, and pleasant environment. Some of these devices generate ions by using complicated wire grid arrays or high voltage electrode arrays. Some use fans and similar devices for moving air. Some of these prior art devices are mounted in large housings that contain fans, filters, and other complicated moving parts. Often, the devices become clogged with pollutants, which requires disassembly of fan assemblies, replacement and/or repair of high voltage sources, extensive clearing of arrays of wires and electrodes that help create air movement, and replacement of filters that clog the devices unless they are cleaned. These devices are often larger, noisier, more complicated, and more expensive than what some users may desire. Often, the location of the device is an issue, as consumers want air cleaning in all rooms of the house. Further, placement within a room is also problematic, as consumers often perceive that stationary air cleaners do not clean the entire airspace of a room and the air in corners of the room would remain stale.
However, even with air purifiers operating in a room, over time airborne contaminants settle upon surfaces. These collections of dust, dander, pollen, and other contaminants are a common problem in dwellings, office spaces, and other work or domestic locations. Such collections of surface contaminants are unpleasant and, on many occasions, may also represent a health problem for many asthmatics and allergy sufferers. Therefore, because air purifiers can only collect contaminates contained in the air, floors and other surfaces on which these contaminates collect must be cleaned periodically to remove them. In most cases, this is carried out manually by sweeping, vacuuming, or dry-mopping. However, such tedious manual activities can be counterproductive, in that cleaning tends to release the surface contaminants as particulates back into the air and thereby increase the concentration of airborne particulate, which in turn decreases ambient air quality.
Robots have long been used as a suitable replacement for manual activity in a number of situations. Recently, robots have being used for practical household cleaning applications. An example of a robot used for autonomous mobile surface treatment is found in U.S. Patent Application Publication No. 2003/0126701; (the '701 application), entitled, “Mobile Robot.” The '701 application describes a mobile robot that is capable of autonomous movement across a surface by means of a drive unit that is arranged inside a top-hat-shaped unit. Cleaning devices, such as electrostatic dusters or equipment for vacuuming, can be affixed within the top-hat structure, so that the mobile robot functions as a cleaning robot. One aspect of the invention of the '701 application is to provide a mobile robot which, during a given period of operation, can remove a substantial part of the dust particles that can be found on floor surfaces. However, the robot disclosed in the '701 application does not provide a means of air filtration or other air treatment methods in order to minimize airborne particulates and reduce the overall indoor air contamination.
In comparison, U.S. Patent Application Publication No. 2002/0078830, (the '830 application), entitled, “Air Purifier,” describes an intelligent air filtration unit that adapts its operation, based on air quality. When the unit senses that the air quality condition is poor, or is deteriorating, it increases filtration, and when the unit detects that the number of particles per unit volume of air has decreased to a range of acceptable or good air, it automatically reduces filtration. Therefore, the apparatus disclosed in the '830 application provides air filtering as a function of air quality. However, the apparatus of the '830 application does not address surface contaminants and it is not automatically mobile.
In addition to cleaning the air and surfaces of contaminants, another aspect of air purifying or freshening that is of interest to consumers is that of removing odors or providing fragrance to the air. Technology exists to deliver each of these benefits separately as well as in a single product form. In practice, unpleasant odors can be removed or can be modified to exist as a more pleasant scent. Odor modification is frequently accompanied by the addition of a more agreeable scent. Air fresheners are typical odor modifiers, because they employ volatile fragrance agents for odor control by altering a malodor to a more pleasant character or to an acceptable level. Air fresheners were initially used in bathrooms and kitchens and, consequently, the device shape and design has tended to be more functional than attractive. Air fresheners typically ensure a consistent fragrance refill revenue stream for the device manufacturer. Air fresheners are now used in bedrooms and living rooms, however consumers who wish to use air fresheners in these areas of the home may be reluctant to place an unattractive, functional container in these areas.
Thus, it is desirable to develop an autonomous and mobile floor cleaning mechanism that is easy to operate and removes surface contaminants from surfaces without reintroducing a significant amount of the particulates removed from the surface into the air and, consequently, reduces the required frequency of manual cleaning. Further, as a result of the relationship between airborne particulates and surface contaminants, it is also desirable that both air filtration and surface cleaning be performed in a single device. Additionally, as it is desirable to provide the air with a selectable fragrance, it is also desirable that the autonomously mobile air purifier in combination with a surface cleaner include a fragrance providing mechanism in a single device.